U(III)-Acetylacetone complex 1 was prepared and characterized by elemental analysis, UV/Vis, IR, ¹H-NMR spectroscopy, conductance and magnetism. The spectral results indicated that the composition of this complex is [Eu(acac)₂(NO₃)(EtOH)₂(H₂O)₂].We development simple, sensitive and selective spectrofluorimetric method for the determination of trace amounts of bumetanide in pharmaceutical tablets and biological fluids (serum and urine) using complex 1. The bumetanide can remarkably enhance the fluorescence intensity of the complex in acetonitrile at λ_ex/Em = 385/619 nm and pH 7.1. The dynamic ranges for the determination of bumetanide concentration were found from 1 x 10^-11 to 1 x 10^-4 mol L^-1, and the limit of detection (LOD) and quantitation limit of detection (LOQ) are 1.6 ×10⁻¹⁰ and 3.2 x 10^-9 mol L^-1, respectively.